Zaelum
this is odd. if I'm not mistaken then Mc should have speed and reaction time similar to Sonic from OPM and durability similar to Darkness from Konosuba. If both are true then he should have Zero difficulty against anyone in the East Blue and the first couple islands in the Grand Line. this is because Darkness can tank explosion magic from Megumin and Sonic was a mid to high Tiger level threat mostly because of his speed, which should be significantly faster than Kuro btw, despite his low durability.